Lubricating grease composition



Patented July 22, 1952 Arnold VJ. im m, Clarl e'Town ship," mm

County, David W'. 'Young Roselle; and Delnier Gottle}. Highland Park;-, ,N-. Jaassignors to Standard Oil Development .Com'pany a some ration of Delaware viscosity indices, their extremely low -p'ourpointsj and their 1 cheniical' st'ability make" them ofg'reat value in specialized lubrication-- problems.

It has been known that these synthetic esters may -be -usedfor the preparation of lubricating grease compositions: -One suchgrease composition is described in- U. -S.- Patent- 2,436,347 issued omFebruary 17. 1948 to J C. Zimmer. andrA J Morway Theapreparation of these synthetic ester; base greases however, is difiicult and involves the use. of large amounts ofsoap in the order of 1- 2-21% byweight Ordinarily, it; is also necessary to-usefrom 0.5-5 of a stabilizer in these synthetic: esterbase greases; for-example an amphoterict metal compound such. as anoxide. carbonate or' soap of. zinc oraluminum; v l ltQhaisjhowheen found-pandj-forms the. object. ofthis invention. that these desirable synthetic ester. base grease compositions may be prepared using relatively minor. amounts ofiflthe usual gr'easeJforming soaps. by .util'i'zihgthei novel oil' thickening properties of' an lST-aeyhp-amino phenol having. certain specified. carbon chain lengthsv inf the. aliphatic portion thereof.

' The technique ofIthepreparation-of these novel lubricating grease compositions is very simple. The synthetic ester'lubricant'chosen is admixed with from about 1-6 by' weight of an alkali metal or alkaline e'arth metal soap or a high molecular weight substantially saturated .fatty acid and? heated to a temperaturewithin a range When the mixture ofzsynthetic'i ester: and soap has cooled to approxi'nriarely- 250'" F; the" oilamino phenol mixture is added and the whole mass allowed to cool to room temperature, resulting in a clear solid grease structure.

Among the syntheticester lubricating. oils op-' jmini atfm g man:mammals;.

. se i-a1-No.202 .422 Ff-Gianna (01. 252-421) erablefor' the preparation ofithegreaslefs vehtion may beany'ofithe aliphatic :dibasic esters havingr thergeneraluformulaz; w

EQOGRGQORX wherein, is a. bivalent aliphatic hydrocarbon radicalsuch. as methylene} polymethyl'ehe, ethylidene, propylic'lene, .methyl' dimethylene, .butyl;

' idene and. the, like. andiwherei n RZ' and'Bi" are branched chain hydrocarbon. radical'sfjliavfiig from 4.to-22.carbon.atoms. and may besal'ikfejor diffk'arentwv Examples of som'of the synthetic esters. operable," and. covered? the...form'ul"a;-

above. are the esters of adipiciacidi sube'ric acid... azelaic acidlandsebacic acidl Other synthticoils which may be'lised asbas'estoclis 'for the preparation of'ivery satisfactory grease compositions according; to the inventive concept ihcl'u'de the pblye'tlier'sl's'uch a'sjthef poly;- glycol ethers and complex ester sucha's the esters ofalkylatediisuc'cifiic a'cid; OX0 aloe;

general formula- 1 Nes'tearoyl-z .p-ramino phenol, and: ,N-arachifdoyl p-amino phenol, N-stearoyl p-amino phenol is especiallypreferred; l i j The alkylated 'N-acyl p-aminophenols, exemplified by the formula above where R and R" are alkyl groups containing from 1 to 20; pref.-

erablyr 4-15, carbon atoms, are also operable in. a

the instant invention. Compounds such as N-n valeryl-4- amino-3-pentadecyl phenol, N-n-propanoyl 4 amino 3 pentadecyl phenol, N-npentanoyl 4 amino 2,6,di tert. -j'butyl phenol, N-n-hexoyl-4-amino-2 -hexyl phenol are exbricating grease composition was prepared ac cording to the following formula? 2 6.0% lithium stearate 2.0% stearoyl p-amino phenol 23.0% refined naphthenic distillate having a viscosity at 210 F. of 35 S. U. S. and a pour point of 45 F.

69.0 Di-'2-'ethy1 hexyl sebacate Standard inspection tests on the grease of Example I gave the following results- I Dropping point Q. F.... 360

, Water solubility (30 min. at 210 F.) Nil m-amino phenol which may thenfbe purified by 7 any of the various methods known to the art; An example of the preparation of on e'N-acyl p-amino phenol is'g'iven below; TQn e' mol of pamino phenol was-placed in a glass roundbottomedfiask equipped with a reflux condenser with an az'eotropic take-offside arm. To the flask was then added one mol of stearic acid and 50 grams of xylene; The xylene served as an entraining agent to remove, azeotropically, the water of the reaction. The flask was heated to. th'e xylene refluxing" temperature for; about five hours, or until such time as the theoretical water (1 mol) was .removed. {The round bottomed flask was then emptied into an evaporat lng dishand the'mixture heatedon a steam bath untilthe last traces of xylene were removed. The compound was then recrystallized from glacial acetic acid and there resulted colorless N-stearoyl p-aminophenol. a i j :Aswas mentioned above, the greases of this invention are prepared simply and easily by a blending or mixing operation of two components. Onecomponent is a mixture ofithe chosen synthetic ester'anda'soap'. The synthetic ester may Q lng'from 1% to'6%i preferably8 to.6% by Weight.

This mixture is heated to a temperature within Penetration: (mm/ 10 at 77 F.) unworked 280 Worked- '60 strokes ASTM worker 310 80,000 strokes ASH! worker 340 Example II I By the same procedure asv in Example L a grease having the following formula was pre-l pared.

4.0 lithium hydroxy stearate 7 2.0% N-palmitoy1p-amino phenol V 18.0% refined naphthenic distillate havinga viscosity at 210F.of 35 S. U. S. and a pour point ;of F. 2;

76.0% C8 0x0 alcoholester of sebacic acid.

To summarize, this-invention relates 'to new anduseiullubricating grease compositions and a method of their manufacture having desirable properties of stability, fluctuating temperature a range of from 350 to 480 F. with stirring, at

ods and there results a stabletranslucent grease composition of excellent appearance. ."(The p,er-

weight of thetotalcomposition.) i

centages given above are byweig ht, based onthe 'EaiampleI renewin the-procedure .nhumed above a 111 lubricating and-the like which consists essentially of a synthetic ester thickened to a grease consistency with a minor amount of a soap and.

from 1.0% to 12% byweight of an N-acylpQ-amino I phenol having'from -16 to 22v carbon atoms in the acyl portion thereof. The greases are prepared by mixing the amino phenol with a small amount of a mineral oil and blending this mixture with the synthetic ester containing dis persed therein a minor amount'of an alkali metal or an alkaline earth metal soap of a high mo lecular weight substantiallysaturated fatty acid.

1. A lubricatinggreasei I from about 34% to 79% by weight of asynth'etic ester having the generalformula" v 'j wherein R is a bivalent hydrocarbon radical of.

vthe class consisting of methylenefpolymethyl- 'ene, ethylidene, propylidene, and methyl 'dimethylene radicals, and i R .and'iR"- are branched chain hydrocarbon radicals having of a material having the fqxmu g wherein R is an aliphatic hydrocarbon radical 1 containing from 16 0022 carbon atoms composition comprising mineral oil' solutionof fromfl to 12% by weight ROOCRCOOR" wherein R is a bivalent hydrocarbon radical of the class consisting of methylene, polymethylene, ethylidene, propylidene, and methyldimethylene radicals, and R and R are branched chain hydrocarbon radicals, alike or different, containing from 4 to 22 carbon atoms which has been thickened to a grease consistency with (1) a solution of about 14% to 53% of a mineral oil and about 1% to 12% of an N-acyl p-amino phenol having from 16 to 22 carbon atoms in the acyl portion thereof, and (2) about 1% to 6% of an alkali metal soap of a substantially saturated fatty acid; percentages being by weight, based on the Weight of the total composition.

3. A lubricating grease composition consisting essentially of about 64% to 73% of an ester having the general formula- R'OOC (CH2) sCOOR" wherein R and R. are branched chain hydrocarbon radicals having from 4 to 22 carbon atoms which has been thickened to a grease consistency with (1) about 3% to 6% of an alkali metal soap of stearic acid and with (2) a solution of about to 30% of a naphthenic mineral oil and about 1 to 6 of an N-acyl p-amino phenol, the acyl group of which contains from 16 to 20 carbon atoms, percentages being by weight, based on the weight of the total composition.

4. A lubricating grease composition according to claim 3 wherein the metal soap is lithium stearate and the p-amino phenol is N-stearoyl p-amino phenol.

5. A lubricating grease composition consisting essentially of about 69% of di-2-ethyl hexyl sebacate thickened to a grease consistency with about 6% of lithium stearate, and a solution of about 2% N-stearoyl p-aminophenol in about 23% of a naphthenic mineral oil, percentages being by weight, based on the Weight of the total composition.

6. A process for the preparation of ester base lubricating compositions which comprises the steps of admixing with from 34% to 79% of an ester material having the formula- R'OOCBCOOR" wherein R is a bivalent hydrocarbon radical of the class consisting of methylene, polymethylene, ethylidene, propylidene, and methyldimethylene radicals and R and R are branched chain hydrocarbon radicals, alike or different, containing from 4 to 22 carbon atoms from 1% to 6% by weight of a metal soap of a high molecular weight substantially saturated fatty acid, heating the mixture while stirring to a temperature within a range of from 350 to 480 F., cooling the mixture to a temperature of about 250 F., blending therewith a mixture of about 14% to 53% of a naphthenic mineral oil and about 1% to 12% of a material having the formula n HOQNCOR said mixtur having been heated to a temperature of about 250 F., and cooling the resulting blend to obtain a stable grease composition, percentages given being by weight, based on the weight of the total composition.

7. A process for the preparation of synthetic oil base lubricating grease compositions which comprises the steps of admixing with from 64% to 73% of di-2-ethyl hexyl sebacate, 3 to 6% of lithium stearate, heating the mixture with stirring to about 350 to 480 F., cooling the mixture to a temperature of about 250 F., blending therewith a mixture of about 15% to 30% of a naphthenic, mineral oil containing dissolved therein about 1 to 6% of N-stearoyl p-amino phenol said mixture having been heated toabout 250 F., and cooling the resulting blend to obtain a stable grease composition, percentages given being by weight, based on the weight of the total composition.

ARNOLD J. MORWAY. DAVID W. YOUNG. DELMER L. COTTLE.

REFERENCES CITED The following references are of record in the file of this patent:

V UNITED STATES PATENTS Number 

1. A LUBRICATING GREASE COMPOSITION COMPRISING FROM ABOUT 34% TO 79% BY WEIGHT OF A SYNTHETIC ESTER HAVING THE GENERAL FORMULA- 